Yesterday we wrote about a Japanese study from 2006 in which supplementation with 3 g glycine improved the quality of sleep without side effects. The subjects felt more clear-headed the next day instead of being drowsy. Researchers at Ajinomoto and Jikei University in Tokyo went a step further in a study they did in 2007. They discovered that memory functions better after glycine-improved sleep.
Glycine [structural formula shown above right] is a non-essential amino acid. It’s the smallest amino acid, which the body makes by converting serine, but it’s also found in food.
Gelatin for example consists of 22-25 percent glycine. If you want to consume 3 g glycine, and don’t have glycine supplements available, then 12-14 g gelatin would do the trick.
Animal studies have shown that glycine supplementation is safe. The LD50 – the single dose at which half of a group of rats dies – is 7.9 g glycine per kg bodyweight. That’s high.
The researchers published in 2007 in Sleep and Biological Rhythms the results of an experiment in which 11 subjects aged 30-57 participated. On one occasion the subjects took 3 g glycine an hour before hitting the sack; on the other occasion they took a placebo.
The next day the participants reported that they had slept better after taking the glycine supplement. To put it more precisely: the subjects felt they had fallen asleep more quickly and had woken less often during the night after taking glycine. During the day following a night of glycine-aided rest, the subjects felt more alert.
The researchers monitored the sleeping behaviour of the subjects, and noticed that the glycine supplementation had a subtle but positive effect on the sleep pattern. The subjects slept more quietly as a result of the amino acid [Awake/Microarousal was less] and did indeed fall asleep more quickly [Stage 1 was shorter].
The researchers also discovered that the glycine-enhanced sleep also led to an improvement in memory function. The subjects were given a test in which they had to remember letters or numbers that they had seen previously on a computer screen.
The researchers monitored the sleeping behaviour of the subjects, and noticed that the glycine supplementation had a subtle but positive effect on the sleep pattern. The subjects slept more quietly as a result of the amino acid [Awake/Microarousal was less] and did indeed fall asleep more quickly [Stage 1 was shorter].
The researchers also discovered that the glycine-enhanced sleep also led to an improvement in memory function. The subjects were given a test in which they had to remember letters or numbers that they had seen previously on a computer screen.
“The importance of a good night’s sleep is not in doubt”, the Japanese conclude. “The use of chemical hypnotics is widespread, although they have well-known problems.”
“Therefore there is a need for a safe and reliable sleep regulator for those occasions when sleep is disturbed. Our present results suggest that glycine produces subjective and objective improvement of sleep quality and leads to a natural sleep pattern, including an early appearance of slow wave sleep and maintenance of REM sleep.”
Glycine ingestion improves subjective sleep quality in human volunteers, correlating with polysomnographic changes
Abstract
In human volunteers who have been continuously experiencing unsatisfactory sleep, effects of glycine ingestion (3 g) before bedtime on subjective sleep quality were investigated, and changes in polysomnography (PSG) during sleep were analyzed. Effects on daytime sleepiness and daytime cognitive function were also evaluated. Glycine improved subjective sleep quality and sleep efficacy (sleep time/in-bed time), and shortened PSG latency both to sleep onset and to slow wave sleep without changes in the sleep architecture. Glycine lessened daytime sleepiness and improved performance of memory recognition tasks. Thus, a bolus ingestion of glycine before bedtime seems to produce subjective and objective improvement of the sleep quality in a different way than traditional hypnotic drugs such as benzodiazepines.
Source: http://www.ergo-log.com/improve-sleep-glycine-memory-will-work-better.html
